Polarized light can improve vision systems and can be used in televisions, computer projectors, medical vision systems, military vision equipment, etc. It can be beneficial to have adjacent polarizing sections, such as adjacent wire grid polarizers, that have a difference in angular orientation of the wires between the different sections. This can allow the light to be polarized in a different direction through different sections. This difference can be used to provide real-time, multiple views of an object. For example, see U.S. Pat. Nos. 6,075,235 and 7,375,887. Although the different polarization due to different wire grid angles is helpful, it would be beneficial to have more real-time views of an object than can be provided by adjacent wire grid polarizers with different wire grid angles.
It is beneficial for a wire grid polarizer to have high transmission of one polarization Tp and low transmission of another polarization Ts. Some structural characteristics of wire grid polarizers, such as a decreased wire height h, increases both Tp, which is usually desirable, and Ts, which is usually undesirable. Other structural characteristics of wire grid polarizers, such as increased wire height h, decreases both Tp, which is usually undesirable, and Ts, which is usually desirable. Thus, there can be a trade-off between optimization of Tp and optimization of Ts. For some vision equipment, it would be beneficial to have adjacent wire grid polarizers in which one is optimized for Tp and an adjacent section is optimized for Ts.
Polarizers optimized for one wavelength, or range of wavelengths, may not be suitable for polarization of another wavelength, or range of wavelengths. Objects appear differently under different wavelengths of light. For example, visible, ultraviolet, and infrared light emanating from an object, or even different wavelengths within visible, ultraviolet, or infrared can be detected and compared for analysis of the object. It would be beneficial to have a polarizer optimized for each of these wavelengths or wavelength ranges.